Dynamometer.



A. E. S. CRAIG. DYNAMOMBTER.

APPLICATION FILED NOV. 2.1908. l 943,391 v Patented Dec. 14, 1909.

4 SHEETS-SHEET l.

A. E. S. CRAIG.

DYNAMOMBTER.

APPLIUATION FILED Nov. 2, 190e.

Patented; Deo. 14, 1909.

4 SHEETS-SHEET Z.

figg-'2? -Sneedfeet perSec.

A. E. S. CRAIG.

DYNAMOMETBR.

APPLIQATION FILED Nov.2,19oa.

Patented Dec. 14, 1909.

4 SHEETS-SHEET 3.

am? .4f/21 of ze@ TTUHNEYS.

A. E. s. CRAIG.

DYNAMOMBTER.

APPLIGATION IILED NOV.2, 1908.

943,391 Patend nec. m09.

.ARTHUR EDWARD STEWART CRAIG, 0F WESTEALINCQENGLANB.

DYNAMOMETER.

Specialization of Letters Patent. Patented Doc. ll, lllllll.

Application filed November 2, 1908. Serial No. y.-lttlf.

T o all whom t may concern:

Be it known that l., ARTHUR EDWARD STEWART Cnam., a subject of the Kingof England, residing in fest Ealing, in the county of Middlesex andKingdom of .England, have invented certain new and useful Improvementsin Dynamometers, of which the following is a specification.`

My invention relates to improvements in dymunometers and has for itsobject to provide a dynamometcr which shall indicate brake horse powerorits equivalent without calculation on the part of the operator, and isintended more especially to be made in a convenient form for testingprime movers ,by applyin the apparatus to the periphery of the tlyw eelsor pulleys of same. p

In order that my invention may be clearly understood I have shown in theaccompanying drawings a' convenienty forni of apparatus, in which-Figure l is a side elevation partly in section ot the apparatus, Fig. 2is a'plan view thereof, Fig. 2a is a View of the chart or dial.

Fig. 3 is a part transverse section on, the line A-B, Fig. l, and Fig. 4is a' part transverse section lon the lineC-D, Fig. 2.. Figs. .5 and 6show a modification of the scale and pointer in side and end elevationrespectively, and Fig. 7 shows a further alternative form of scale andpointer.

According to my invention, and referring first to Figs. l to 4 of thedrawin s, Imount one or more wheels, disks or lrol ers a on a Y shaft orspindle b arranged in such a manner on a suitable arm or arms c thatlthe shaft or spindle?) will revolve when the one' or more wheels, disksor rollers a is or are 'applied in frietional contacttorthe periphery ofthe flywheel or pulley l of the engine or other machine yof which it isr the brake horsepower developed. Hence the revolutions of the shaft oryspindle b will Vary relatively to the peripheral speed' of the flywheelor pulley d a amst which it is held. The shalt or spin le b carrying thefriction wheel orrdisk 'a is mounted on the swinging arm or arms c whichis or are attached .or pivoted at o1 to a main lever orl .frame e andthe said arm or arms o is are preferably kept against thel'lywhcel (Z byan adjustable spring f (Fig. 2). This shaft or s indle b is utilized todrive a suitable device which will indicate proportionate variations ofspeed, as for instance a centrifugal action sensitive governor g, showndiagramrthe pinion o (F ig. 2).

uired to find matically in Fig. 3. This device actuates in a varyingdegree according to speed a pivoted arm It which may be attached at itsY oppositeextremity to a Bowden wire z', such wire passing if desiredthrough the swinging arm c and being carried to the pointer whichtravels across and above tie dial or scale lf in suitable guides. Ity w1l be seen that with this device it isnot necessary to know therevolutions perminute as has been previously ascertained, the peripheralspeed 1n feet per second being alone transmitted. Also mounted on themain lever c is a cradle or Jrame that is fixed in such a manner as tobe capable of a limited movement as vfor instance by being attached toswinging links l at either end, and this cradle or frame carries aflexible friction band 'm that' is pressed by the action of the lever ewhen the dynamometer is used against the periphery of the llywheel orulley d oi the engine or other machine to e tested. The limited movementmaybe transmittedby a rack and pinion arrangement; thelower rack 'n isfixed and the pinions o on the cradle shaft p mesh therewith, the upperrack g being movable and also engaging with The cradle 1s arranged sothat the exible friction band m adjusts-r itselt automatically to suitthe periphery of any Wheel Within the limitsof the apparatus. The cradlein meshing in the lower, racks n and working along the saine doubles themovement imparted to it in pulling the u perf rack g, that is to say,the movement o the upper rack g is twice that of the. cradle on thelower racha.A To any convenient portion of the friction band,

A'or cradle or frame,\such as the underside of the flexible band m is'attached an instru ment such as a spring balance or a calibrated tensionspring 1' that will indicate variations in peripheral pull. The upperrack g 1s connected by suitable means such as a rod s to the scale ordial k. At or about any convenient portion of the main lever e. isarranged a scale or dial such as lo calibrated in such a manner that thecombined varia.- tions of eripheral speed and pull obtained by suchyeviccs-ashereinbefore described are indicated" direct as resultantbrake horse power or whatever other equivalent term may be used. A chartis arran ed on this scale in which the vert-ical lines will give thepull in pounds and the horizontal lines the speed in feet. per second,as shown in Fig. 9.. The

dial 7c moving in one direction according to the pull and the pointermoving across the dial according to the speed will plot out a suitablecurve. By referring to the table on the side of the chart givingtheresultant horse power of alarge series of the factors,'- speed and pull,by ollowing the chart lines vertically and horizontally at any lpointwhere they are intersected by the diagram marked by theencil and readingthe ligures on the edge otP the chart the nearest horse lpower can 4befound at a glance.l Or the horse power can be printed on the face of'the chart at intersecting points in small figures.

Figs. 5 and 6 show a form of scale in which the chart is held on a drumor cylinder t, or a segment of same, the pull giving a rotary motion tothe drum t through rack g as before.' The drum is so `arranged inrelation to the arm 71,1 actuated by the speed indicating mechanism asbefore that the arm acts as a pointer jl and moves across the face ofthe chart thus .giving thel required readings. c is a spring to pullthescale holder back. 4Therefore the two indicating devices controlledrespectivelyby the `Speed and the pull of the engine or other machine tobe tested work simultaneously butin a; multiplying manner with regard toone another, so that by reading oilL1 suitably4 lcalibrated figures 'onthe scale opposite a hand or pointer or a 'mark on a second scale thedirect reading of brakev horse power or its equivalent-may be obtainedwithout calculation.

Fig. Z is another form of dial for giving the readings where the scaleand pointer moveinopposite and multiplying manner.

The calibration is here in accordance with.

logarithmical progression, the scale being rotated through rack andlpinion or pulley or other equivalent device by the pulling mechanism,while the hand or. pointer is .caused .to follow the counter of a slotand isV linoved in an opposite directionby the speed ,indicatingmechanism. The slot ishere of spiral form instead of circularto .preventthe hip7 herreadings beine' unduly crowded. In this figure, 8 is thedial slotted as at v9 and calibrated on oneedgey of the slot. 1Whencircular motion is given. tothe `shaft 10 (with square attachedyby meansof the are mounted/and arranged may be f any convenient length, shapeand materiiil and is preferably inserted under the flywheel or pulley dof the engine or other machine to lbe tested. It is arranged as'a leverlof the .second kind and haspreferably its fulcrnm at or about the endthat is passed underneath the flywheel or pulley as shown at w so thatthe resultant of bothv may be applied to any "other convenient form of dnamometer in which itis desirable to indicate the brake horse power or.its equivalent of any engine or other machine directly. ,y

vWhat I claim as my invention to secure by Letters Patent of the UnitedStates is:-

comprising, in combination, means for ascerta-ining the tangential pullof the ywheel or pulley at the periphery, al single scaleor dial, andmeans for ascertaining the and desire A y 19o 1. A dynamometer of theabsorption type peripheral speed of vthe said flywheel or pulley, meansfor conveying said indica- 'tions of pull and speed to said scale ordial,

.said scale ordial having means for ascertainingfrom saidiscale or dialwithout cal culation `on the part of the operator 4the brake horse-powerof the machine 'being tested. I

2. A dynamorneter of the absorption type comprising, in combination, alever,a cradle located thereon .and capable of a limited movement, aflexible friction band on said cradle, said cradle automaticallyembracing a segment of the wheel orl pulley when pressed in contacttherewith bysaid lever, means connected to said cradle to ascertain' thetangential pull of the flywheel or pulley at the periphery, means forascertaining the peripheral speed of the .said flywheel or pulley, a.single 'scale or dial, and means for conveying said indications of pulland speed` to said scale ordial, said scale ordial having means forascertaining from said scale or dial. without calculation on the part ofthe operator the brake horse-power of the machine being tested.'

A dynamometer .of the absorption type comprising, in combination, alever, means for ascertainin the tangential .pull of the vflywheelor'pnl ey at the periphery., springcontrolled arms pivoted to saidlevera friction wheel carried by said; arms adapted vto contact with theperiphery of the said ilywheel or pulley, speed-indicating ap aratnsactuated by the friction wheel, a sing e scale' o1' elia-l, a nd meansforr eon\e\/inr said indieations of pull and speed to said seale or(tial, Said scale o1' (lial having means for ascertaining from saidseale oi' dial without Calculation on the part of the operator the brakehorse-poney of the machine being tested.

4. A dynanlolneter of the absorption type comprising, in combination, alevel' of the Second ,order normally lying;l clear and adapted to bepulled up at the actuated end into Contact' Vith a flywheel or pulley,means for ascertaining the tangential pull of said Hywheel or pulley atthe periphery, means for ascertainingl the peripheral speed of the saidflywheel or pulley. a single scale or dial, and means for conveying saidindications of pull and speed to said `scale o1' dial, saiil seale ordial having means for ascertaining' from Said Scaleoi dial withoutcalenlation on the part ol` theopeiatolthe ln'ahe borne-poneioll thelnaehine beinel tealeil.

5. A lynainolnetel' ol the absorption type imprininggp in eoinbinat ion.means tot ascertaining' the tangential pnll ot a flywheel or pulley atthe periphery. a Angle .st-aley or ilial, and ineans for aseertainingthe peripheral speeil of the will ltywheel o1- pulley, meansl'ofeonveyinesaid indications ol' pall :unl speed to saiil seale. oi'lial7 said .scale o1' ilial having mean foi' enabling;l the resultantJhorse-poner of the inaehine to be *een at a glance without calculation.

In testimony, that l elaiin the foregoing aa nxy invention. l havesigned 1ny7 naine 35 in present-e of two subscribing witnesses.

ARTHUR EDWARD STEWART CliAlG. Witnesses J. h'. Almen, F. BLAnnY.

